That video clearly shows the curve in the road I mentioned, but the bike might be on a straight section in still above. The video also clearly demonstrates how easily the bike headlight is visible compared to that of the car headlights. It also shows how much overlit the taillight system is, in my opinion. So if a theoretically 600 lm headlight is that bright from that distance, immagine how bright two theoretically 900 lm lights would be! Then another one on a helmet, pointing at your face while sitting at a red light? That's why I say that LED bike headlights can certainly be too bright, when used on the road. More is not always better.

The baffle you put in front of the reflector in your headlight didn't work because the light it blocked was mostly comming off the reflector and heading toward the hot spot formed by the reflector. I guarantee you made the hot spot dimmer by almost half. The light that's called "spill" comes directly from the source, and "spills" over the edge of the reflector. Also, there's diffraction off the edge of your baffle that only shows up in the far field.

To effectively make a cutoff beam, you'd want to make the reflector itself flat on the top, while keeping its shape for focusing the hot spot beam in the center of the pattern. You could also use a multisegmented lens in front of the reflector, properly shaped sub-reflectors on the main reflector profile, or maybe a lens up real close in front of the source.

The video also shows, quite clearly, that the position of the bicycle light causes no glare problems for on-coming traffic. The light is easily visible from across the road but at no point is there any possibility that the light would blind a driver from that location.

I know how bright my lights are. I also know that my lights don't come anywhere closer to on-coming traffic than a normal passenger side light on an automobile would. How, you might ask? Because I can see where the light is going. Two bright lights set next to each other (less than 6 inches apart) aren't going to spread the beam any more than the light you see in mechBgon's video. They are going to be brighter certainly but that makes the road easier to see from the saddle.

I also have valid reasons for running multiple lights. I've had far too many failures to depend on just one lamp. Sometimes even 3 isn't sufficient, as I experienced when I crashed a couple of weeks ago and broke all three of my light mounts. The fact that the helmet light mount didn't break completely through is the only reason I didn't have a long dark walk home.

Without any evidence, you claim that I am "belligerant, selfish and inconsiderate" in the use of a helmet light. Nothing could be further from the truth. When sitting at a light, my helmet lamp is tilted up away from driver's eyes. I don't point my light in anyone's face unless absolutely necessary to keep me from being harmed by an inattentive driver. I, and probably most people who use helmet lights, know exactly where the light goes and exactly what it can do. We don't use them as weapons except in extreme cases. You've been informed of this many times and continue to ignore it.

You have also been informed...again many times... that the statement 'More is always better' and 'retinal burners' were meant as jokes. I coined the term 'retinal burners' as a silly means to convey the brightness of my overvolted halogen system. It does not mean that the lights have any retinal burning capability. They don't put out that kind of power

Finally, if you wish to buy the 'maximum lumens/dollar' for your own use, feel free. Allow the rest of us to make that same decision to meet our needs. We'll assume that you use your lights responsibly if you make the same assumption about everyone else.

Amazingly, I fully agree with you on why a simple baffle won't work. Your second statement also demonstrates why cut-offs like the e-code cut-off would be impractical for bicycle lamps. The amount of money required for development of the reflectors and lenses would drive the price per unit impossibly high with little return on the investment, mostly because not many people would buy a $2000 light.

I don't believe you're "always" in that much control of your head mounted light, or that "most people who use helmet lights, know exactly where the light goes and exactly what it can do." That's my opinion, and it's based on what I've observed amongst "The Cyclists", people aiming laser pointers at aircraft, people failing to aim or dim their headlights, people having problems aiming their bike headlights properly, people using flashlights foolishly, and people having general disregard for light pollution or light tresspass. People generally haven't got a clue where their headlights are pointing, because it's really misleading to judge it upon reflection off irregular objects from the source location. I've ignored those assertions of yours because they deserve it.

The "retinal burners" "joke", and your steadfast refusal to consider the need for restraint with light, tells me it wasn't a joke to you until I had the gall to "question your authorita" regarding bike headlights here. Prove me wrong by showing a post predating my "more isn't always better" post in response to you. You know which one I'm talking about.

edit: comments deleted, as they're perpetuating a thread derailment here.

cyccommute, Rapid Robert...

Take it to PM.

+1000.... These light threads always devolve into I know more than you.. When the OP questions never get answered..

I normally run 2 - p7 lights on my bars with a Q5 on the helmet.. If you aim your lights properly there is not an issue of blinding drivers.. I have read plenty of posts from riders that are aiming there lights 50-100 feet in front of them..If you do this, you will be blinding drivers.. I do not, I prefer that the lights I use be useful to me so I can ride fast at night..

Sigh...RapidRoberts is on his anti-light rampage again. I don't know why he even bothers to post on an "Electronics and LIGHTING" forum in the first place.

To educate the public??? To bring awareness of high brightness light to those who don't work with it every day? To share what I know a lot about? And where do you get that I'm "anti-light"? I'm NOT!

I'm writing for those referred to by Socalrider above: "I have read plenty of posts from riders that are aiming there lights 50-100 feet in front of them..If you do this, you will be blinding drivers..". So why are you derailing this thread with a post about ME, and not the topic?

Enough!
Thread locked.